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Abstract：
The study aimed to identify novel genes for idiopathic hypogonadotropic hypogonadism (IHH).
A cohort of 1387 probands with IHH underwent exome sequencing and de novo, familial, and cohort-wide investigations. Functional studies were performed on 2 p190 Rho GTPase-activating proteins (p190 RhoGAP), ARHGAP35 and ARHGAP5, which involved in vivo modeling in larval zebrafish and an in vitro p190A-GAP activity assay.
Rare protein-truncating variants (PTVs; n = 5) and missense variants in the RhoGAP domain (n = 7) in ARHGAP35 were identified in IHH cases (rare variant enrichment: PTV [unadjusted P = 3.1E-06] and missense [adjusted P = 4.9E-03] vs controls). Zebrafish modeling using gnrh3:egfp phenotype assessment showed that mutant larvae with deficient arhgap35a, the predominant ARHGAP35 paralog in the zebrafish brain, display decreased GnRH3-GFP+ neuronal area, a readout for IHH. In vitro GAP activity studies showed that 1 rare missense variant [ARHGAP35 p.(Arg1284Trp)] had decreased GAP activity. Rare PTVs (n = 2) also were discovered in ARHGAP5, a paralog of ARHGAP35; however, arhgap5 zebrafish mutants did not display significant GnRH3-GFP+ abnormalities.
This study identified ARHGAP35 as a new autosomal dominant genetic driver for IHH and ARHGAP5 as a candidate gene for IHH. These observations suggest a novel role for the p190 RhoGAP proteins in GnRH neuronal development and integrity.
A cohort of 1387 probands with IHH underwent exome sequencing and de novo, familial, and cohort-wide investigations. Functional studies were performed on 2 p190 Rho GTPase-activating proteins (p190 RhoGAP), ARHGAP35 and ARHGAP5, which involved in vivo modeling in larval zebrafish and an in vitro p190A-GAP activity assay.
Rare protein-truncating variants (PTVs; n = 5) and missense variants in the RhoGAP domain (n = 7) in ARHGAP35 were identified in IHH cases (rare variant enrichment: PTV [unadjusted P = 3.1E-06] and missense [adjusted P = 4.9E-03] vs controls). Zebrafish modeling using gnrh3:egfp phenotype assessment showed that mutant larvae with deficient arhgap35a, the predominant ARHGAP35 paralog in the zebrafish brain, display decreased GnRH3-GFP+ neuronal area, a readout for IHH. In vitro GAP activity studies showed that 1 rare missense variant [ARHGAP35 p.(Arg1284Trp)] had decreased GAP activity. Rare PTVs (n = 2) also were discovered in ARHGAP5, a paralog of ARHGAP35; however, arhgap5 zebrafish mutants did not display significant GnRH3-GFP+ abnormalities.
This study identified ARHGAP35 as a new autosomal dominant genetic driver for IHH and ARHGAP5 as a candidate gene for IHH. These observations suggest a novel role for the p190 RhoGAP proteins in GnRH neuronal development and integrity.
摘要：
目的：本研究旨在鉴定特发性低促性腺激素性性腺功能减退症（IHH）的新基因。
方法：一组1387名IHH先证者进行了外显子组测序，家族性,和全队列调查。对2个p190RhoGTP酶激活蛋白（p190RhoGAP）进行了功能研究，ARHGAP35和ARHGAP5，其涉及幼虫斑马鱼的体内建模和体外p190A-GAP活性测定。
结果：在IHH病例中发现了ARHGAP35中RhoGAP域中的罕见蛋白截短变体（PTV;n=5）和错义变体（n=7）（罕见变体富集：PTV[未调整的P=3.1E-06]和错义[调整的P=4.9E-03]与对照）。使用gnrh3：egfp表型评估的斑马鱼建模表明，具有缺陷arhgap35a的突变幼虫，斑马鱼大脑中主要的ARHGAP35同系物，显示减少GnRH3-GFP+神经元面积，IHH的读数。体外GAP活性研讨显示，1个罕见错义变异体[ARHGAP35p。(Arg1284Trp)]具有下降的GAP活性。在ARHGAP35的同系物ARHGAP5中也发现了罕见的PTV（n=2）；但是，arhgap5斑马鱼突变体未显示明显的GnRH3-GFP异常。
结论：本研究确定ARHGAP35为IHH的新的常染色体显性遗传驱动因子，ARHGAP5为IHH的候选基因。这些观察表明p190RhoGAP蛋白在GnRH神经元发育和完整性中的新作用。
方法：一组1387名IHH先证者进行了外显子组测序，家族性,和全队列调查。对2个p190RhoGTP酶激活蛋白（p190RhoGAP）进行了功能研究，ARHGAP35和ARHGAP5，其涉及幼虫斑马鱼的体内建模和体外p190A-GAP活性测定。
结果：在IHH病例中发现了ARHGAP35中RhoGAP域中的罕见蛋白截短变体（PTV;n=5）和错义变体（n=7）（罕见变体富集：PTV[未调整的P=3.1E-06]和错义[调整的P=4.9E-03]与对照）。使用gnrh3：egfp表型评估的斑马鱼建模表明，具有缺陷arhgap35a的突变幼虫，斑马鱼大脑中主要的ARHGAP35同系物，显示减少GnRH3-GFP+神经元面积，IHH的读数。体外GAP活性研讨显示，1个罕见错义变异体[ARHGAP35p。(Arg1284Trp)]具有下降的GAP活性。在ARHGAP35的同系物ARHGAP5中也发现了罕见的PTV（n=2）；但是，arhgap5斑马鱼突变体未显示明显的GnRH3-GFP异常。
结论：本研究确定ARHGAP35为IHH的新的常染色体显性遗传驱动因子，ARHGAP5为IHH的候选基因。这些观察表明p190RhoGAP蛋白在GnRH神经元发育和完整性中的新作用。
